"I have had this gun for about 7 months now and it runs flawlessly(with cleaning it after each day of playing) and I see no reason to upgrade this gun besides maybe some outer upgrades or maybe rewiring it to the front and using a mock peq box. Because you are stuck using nunchuck Batteries that go in the tubes of the crane stock. This gun easily reaches out to your targes and is very consistent with its groupings of 6 inches at 150'. The plastic is of high quality and I'm impressed. The stock sometimes starts to wobble but it's an easy fix by getting a long screw driver and tightening the stock through the buffer tube. The gun does come with 14 mm counter clockwise threads but the Orange flash hider is glued and screwed on very tightly and I had to cut mine off to access the threads. the two magazines that come with it feed very well but midcaps feed even better. The magazines that it's comes with fit very tightly and sometimes may need a slight pat on the bottom to get it in there nicely. They loosen up after a while of taking them in and out. One complaint k have about this gun is the plastic hop up, that is another thing I would want to upgrade, which I did. the rail space on this gun is crazy, there's so much of it. There is one sling mount on the back near the buffer tube for a one point sling. The stubby grip is very comfortable and nice. It has a rubberized texture. The upper receiver fits very tightly with the bottom, the only problem I have with that is getting the one pin that holds it all together in and out. That's a pain. The ROF on this gun is fenominal and the trigger response is even better. I recommend .25 gram bb's in this gun for the best accuracy and performence. The 9.6 volt Battery it came with works great, but make sure you use a smart charger though. Or else you'll justbje throwing your battery away later on. "